Apparatus and method for generating fuel gas from a solid combustible

ABSTRACT

The invention relates to a method and an apparatus for generating fuel gas from a solid material in a shaft gasifier, and comprises a gasification zone, into which the solid material can be filled, and an oxidation zone designed to oxidize the generated gas connected to the gasifier zone so that the gases generated in the gasifier zone run to the oxidation zone. A first air supply device and a second air supply device downstream of the first air supply in the processing direction of the solid material supply air into the gasification zone. A measurement unit samples the raw gas that is generated in the oxidation zone or of the flammable product gas. A control unit, which is coupled with the measurement unit by means of signal technology, transmits a test signal and controls the air supplied by the second air supply device via the test signal.

CROSS-REFERENCE TO FOREIGN PRIORITY APPLICATION

The present application claims the benefit under 35 U.S.C. §119(b) of PCT/EP2013/002765, filed Sep. 13, 2013, which claims priority to German Application 202012008777.0, filed Sep. 13, 2012, entitled “Apparatus for Generating Fuel Gas From a Solid Combustible.”

The invention relates to an apparatus and method for generating fuel gas from a solid material in a shaft gasifier, and comprises a gasification zone, into which the solid material can be filled via a filler inlet, and an oxidation zone designed to oxidize the generated gas, which oxidation zone is connected to the gasifier zone so that the gases generated in the gasifier zone can be run to the oxidation zone. A further aspect of the invention is a gasification process for generating a combustible gas from a solid material.

FIELD OF THE INVENTION

Gasification apparatus of the aforementioned type and gasification processes are used to gasify solid substances, such as organic or inorganic, carbonaceous materials, especially wood, plant, or plant remains, as completely as possible in a controlled process in order to thereby generate an ignitable and, in particular, a flammable gas. Typically, the gas thus generated is burned in a process that is downstream from the gasification in order to thereby perform work and, for example, operate a power generator.

A gasifier and a method of gasification are known from EP 1 865 046 A1, which generate a pyrolysis gas by gasifying the solid material in a shaft gasifier in a three-stage process, which pyrolysis gas is then converted into a raw gas through partial oxidation and thermal breakdown, and converted into a combustible product gas through a process of reduction. In the prior art disclosed in this patent application, the gasification is at times incomplete, in particular in the case of changing properties of the solid material, so that the amount of energy available in the solid material is not fully utilized.

An adjustment and/or monitoring of the quality, especially of the first process, of the gasification by recording the temperature by means of measurement technology, but also through the selection of the specific gas composition and adjusting the supplied air for the gasification process is known from EP 1 865 046 A1. The optimization potential in the case of shaft gasifiers having a multi-stage process chain often lies in the quality/purity of the product gas that is ultimately generated, which is decisive for the subsequent combustion, the need for additional filters, and which is indirectly decisive in terms of the maintenance intensity for the shaft gasifier. A reduction in efficiency may occur as a result of almost unavoidable gas leakage from the gasification zone into the reduction zone, or as a result of changes in the properties of the solid material that is to be gasified during the gasification process.

The object of the present invention is therefore to provide a gasifier and a method of gasification which achieves an efficient gasification of a solid material, and which thereby ensures increased purity of the product gas.

SUMMARY OF THE INVENTION

This object is achieved according to the invention in that the shaft gasifier is refined according to the invention in such a way that a first air supply device and a second air supply device feed air into the gasification zone, wherein the second air supply device is positioned downstream from the first air supply device in the processing direction of the solid material. A measurement unit for detecting a test signal is designed to determine a qualitative or quantitative quantity of predetermined gas components of the raw gas that is generated in the oxidation zone or of the flammable product gas, and which characterizes this in the test signal. A control unit is coupled with the measurement unit by means of signal technology in order to transmit test signal, and is configured in such a way that said control unit controls the quantity of the air being supplied by the second air supply device as a function of the test signal.

The first and second air supply device can supply air to the gasification zone as needed and independent of one another. The measurement device measures the qualitative or quantitative quantity of a predetermined portion of a gas. Here, gas is understood both as a substance, which consists of a chemical element or a chemical compound in a gaseous state (e.g., oxygen, methane, carbon monoxide, etc.), and also as a gas mixture consisting of a plurality of substances (e.g., air). The control unit, which is coupled with the measurement device by means of signal technology, is then able to adjust the air supplied by the second air supply device as a function of the measurement results. The second air supply device thereby is positioned downstream from the first air supply device in the processing direction, since the control of the second air supply device is in response to the already ongoing processes in the gasification zone.

According to the invention, the supply of air in a predetermined level of the gasification zone can be optimized through the qualitative or quantitative quantity of a predetermined gas, which is detected by means of measurement technology, at a selected stage of the gasification process, and it becomes possible to react flexibly to changes in the characteristic properties of the process products while the process chain is ongoing. According to the invention, it was recognized that in this way, a loss of efficiency with respect to the purity of the generated gas, which is caused by an unwanted transfer of generated process materials from the gasification zone into the reduction zone can be prevented. While conventional apparatus and methods are often geared towards preventing the nearly unavoidable transfer of pyrolysis gas from the gasification zone directly into the reduction zone as much as possible, and forcing a path via the oxidation zone, the present invention solves the problem in that the leaked gases that arise are oxidized directly in the gasification zone by supplying air from a second air supply device. The quantity of air from the second air supply device needed is controlled as needed. This is done according to the invention with the help of the measurement device, which directly or indirectly measures the tar content of the raw gas or, respectively, product gas that is generated and, based on the measured values, provides information concerning the level of contamination by non-oxidized pyrolysis gas. The control device, which is connected by means of signal technology, adjusts the supply of air as a function of said measured values.

In the case of the gasification apparatus refined according to the invention, a measurement device and processing by means of signal technology are provided, which makes it possible to draw conclusions regarding the concentration of the leaked gases on the basis of the tar content. In order to reliably oxidize these leaked gases in the gasification zone, the supply of air from the second air supply device can be adjusted as a function of the measured values received via the control unit, which is connected by means of signal technology. In the case of increased tar content in the raw gas that is generated, the supply of air from the second air supply device is increased, while that air supply can be decreased in the event that a measurable tar content is low or is absent.

According to the invention, the measurement unit may also be configured such that it directly or indirectly measures CO content of the product gas that is generated, and the quantity of air that is supplied via the second air supply device can be adapted with the aid of a control unit that is connected by means of signal technology as a function of the measured value that has been processed by means of signal technology.

Like the tar content, in the case of the gasification apparatus thus refined according to the invention, the detected CO content provides information regarding the efficiency of the respectively desired conversion process. The latter is at its highest in the reduction zone when the raw gas from the oxidation zone and the pyrolyzed solid coke from the gasification zone are as hot as possible when they converge, ideally at approximately 1000° C. On the basis of the CO content of the product gas ultimately obtained that has been detected by means of measurement technology, the supply of air can be adjusted by means of processing by means of signal technology by the control unit, which is connected by means of signal technology, in such a way that the coke is once again heated as much as possible before it enters the reduction zone.

According to the invention, the air supply devices can each be used individually, but can also be used in combination with one another. In a preferred embodiment, preceding filtering and/or cooling of the gas may occur prior to the measurement of the gas components in the product gas.

A gasification of a solid material in a large gasification zone is achieved by means of the gasification apparatus refined according to the invention, without the occurrence thereby of an unwanted transfer of the product materials generated, for example non-oxidized raw gas, as leaked gases, or insufficiently heated coke.

The oxidation zone is connected to the gasification zone in order to run the pyrolysis gas that is generated in the gasification zone into the oxidation zone. The gasification zone and the oxidation zone are preferably separated from one another by at least one wall. The connection of the oxidation zone to the gasification zone in order to run the pyrolysis gas that is generated in the gasification zone into the oxidation zone can preferably be created by means of a connection created by means of fluid technology in specific sections, for example by means of one or a plurality of openings in the wall. The process flow of the gasification can be improved by such a design of the gasification apparatus, in particular by such a spatial separation of the gasification zone and the oxidation zone.

In addition, it is preferred that the wall have openings that face obliquely downward, located in an upper part of said wall when in an operating position, via which openings the pyrolysis gas that arises in the gasification zone passes into the oxidation zone as a result of the pressure and flow conditions. The openings are preferably formed in that the sloped wall ends at the height of the respective opening, and is continued just above said opening, being displaced radially inwardly. The thus slightly overlapping, obliquely descending walls of the oxidation zone can thus prevent the unwanted inflow of the solid material into the oxidation zone or a blockage of the opening by the carried solid material.

It is especially preferred that the gasification zone and the oxidation zone be in thermal contact, preferably via the at least one wall, which separates the gasification zone and the oxidation zone from one another. This enables a particularly advantageous utilization of the process heat that is created.

It is provided by means of a first preferred embodiment that, in terms of its cross section, the oxidation zone is at least partially, preferably completely enclosed by the gasification zone. According to this embodiment, the oxidation zone is centrally disposed within the gasification apparatus, in which, in terms of a cross section through the gasification apparatus, said oxidation zone is at least partially, but preferably completely enclosed by the gasification zone. In this way, in particular an annular gasification zone is formed around the oxidation zone, thereby allowing for an effective heat transfer from the gasification zone into the oxidation zone and vice versa. At the same time, it is to be understood that on the one hand, a convective heat transport takes place as a result of the supply of pyrolysis gas from the gasification zone into the oxidation zone, however, in addition, heat transport can also take place through a direct heat transfer as a result of the fact that the oxidation zone is enclosed by the gasification zone. In particular, this embodiment may be implemented such that the gasification apparatus is designed as a shaft gasifier, and such that the oxidation zone is designed as an oxidation chamber that is centrally disposed within the shaft gasifier, said oxidation chamber being enclosed by an annular gasification zone.

In a further preferred embodiment, a temperature measuring unit thereby measures the temperature in or in the immediate vicinity of the oxidation chamber. On the basis of the measurement results processed by means of signal technology, the supply of air into the gasification zone can be adjusted, preferably via the first air supply device so that preferably, a temperature of approximately 1000° C. prevails in the oxidation zone.

Moreover, it is preferred that the solid material can be supplied to the gasification zone in an operating position through a solid material filler inlet solely through the use of gravity.

With an embodiment thus designed, it is possible to achieve an efficient and robust supply of solid material, since there are no mechanical feeders that could disrupt the process in the event of a malfunction.

In addition, it is preferred that the gasification apparatus according to the invention be further refined by a reduction zone, which is connected to the oxidation zone in order that the raw gas formed in the oxidation zone be supplied to said reduction zone, and which is designed to chemically reduce the raw gas supplied thereto. In the reduction zone, a fuel gas can be generated from the pyrolysis gas prepared in the oxidation zone, in particular with the help of coke, which is transported from the gasification zone into the reduction zone, and which is composed of degassed solid residues. In so doing, a filtration of solid particles through the coke in the reduction zone can also be achieved. Alternatively, or in addition to this, other filtering processes may also be provided, for example by means of candle filters or the like.

In addition, it is preferred that the reduction zone having the above or previously explained design be disposed below the gasification zone in the direction of gravity so that said zones are directly connected, and the solid material can pass directly from the gasification zone into the reduction zone under the effect of gravity. In so doing, a section of the oxidation zone should preferably be designed such that said section separates the gasification zone from the reduction zone in the direction of flow of the gas that is generated. As explained above, a fuel gas can be generated from the pyrolyzed and oxidized or, respectively, cracked raw gas from the oxidation zone and, in so doing, an additional filter effect can be achieved in this reduction zone.

A CH₄ sensor represents a preferred implementation of the measurement unit for determining the tar content in the raw gas or, respectively, the product gas that is generated, which CH₄ sensor provides indirect information concerning the tar content contained in the gas via the CH₄ content detected, and which thus be used via processing by means of signal technology in order to adjust the supply of air in the second air supply level.

The pyrolysis gas that is created during the gasification of the solid material is a mixture of carbon monoxide (CO), hydrogen (H₂), water vapor (H₂O), carbon dioxide (CO₂), methane (CH₄) as well as a series of trace gases and impurities in the form of long-chain hydrocarbons (tar). The easily combustible components are oxidized in the subsequent partial oxidation in the oxidation zone. This is an exothermic reaction, and thus the temperature is increased. This temperature can be adjusted to approximately 1,000° C., wherein non-oxidized, long-chain hydrocarbons (tar) break down into short-chain molecules (cracking). During combustion in the oxidation chamber, typical products of combustion such as H₂O and CO₂ are created during the partial oxidation of the easily combustible components. These gases are endothermically converted into H₂ and CO in the reduction zone when they encounter the coke created in the gasification zone. In so doing, the temperature falls, since thermal energy is converted into chemical energy. Non-oxidized and leaked gases that have not been cracked, which circumvent the oxidation chamber, flow through the reduction zone without being involved in the endothermic reactions. They are subsequently found in the finished product gas. The concentration of these impurities can be determined by measuring the CH₄ (methane) content in the product gas.

In terms of the implementation of the measurement unit for the determination of the CO content in the product that is generated, an embodiment is preferred, in which the second air supply device is disposed directly before the transition from the gasification zone into the reduction zone.

A further preferred embodiment provides both an additional air supply device in the region of the gasification zone in order to oxidize exiting leaked gases as well as an additional air supply device directly before the transition from the gasification zone into the reduction zone in order to optimize the heating of the coke.

A further aspect of the invention is a gasification apparatus of the above-mentioned type, which additionally has a gas extraction device, which has a suction opening located to the side on the gasification apparatus, and which is thereby characterized by the fact that the gas extraction device comprises a suction ring, which is configured to have a uniform speed distribution across the cross-section of the gasifier for the gas being extracted, in that the ring provides the gas with a large outlet cross-section on the side facing away from the outlet opening and which tapers on the side facing the outlet opening.

This aspect of the invention can be implemented in combination with the preferred embodiments already described above.

In a preferred embodiment, the extraction device is located such that it is annularly disposed about the reduction zone, wherein the suction ring provides the combustible gas with a large opening on the side facing away from the outlet opening in the direction of gravity, which tapers either continuously or in a stepped manner towards the side facing the outlet opening.

A further aspect of the invention is a method of gasification for generating combustible gases from a solid material, comprising the following steps of supplying solid material into a gasification zone, and gasification of the solid material in the gasification zone by means of pyrolysis or, respectively, gasification supplying of the pyrolysis gas that is generated in the gasification zone to an oxidation zone supplying of air to the gasification zone which is characterized in that the gasification in the gasification zone of air occurs in at least two air supply device, wherein the second air supply device is positioned downstream from the first air supply device in the processing direction of the solid material, and the supply of air via the second air supply device is controlled as a function of the measurement of the qualitative or quantitative quantity of predetermined gases, both pure gases and gas mixtures, in the raw gas that is generated in the oxidation zone or in the combustible product gas. The method of gasification according to the invention may be implemented in particular using the above-described gasification apparatus and is characterized in that it is possible to prevent the unwanted emission of process materials from the gasification zone into the adjacent process zones through the individually controlled supply of air in various levels of the gasification zone.

The method can be further refined in that the supply of air in the gasification zone is individually controlled for gasification sectors that are either regularly or irregularly distributed across the cross-section.

A further embodiment provides for the following additional method steps of supplying air into the oxidation zone and conversion of the pyrolysis gas in a stoichiometric process by means of partial oxidation and cracking into a raw gas in the oxidation zone, supplying raw gas from the oxidation zone into a reduction zone, supplying partially or completely pyrolyzed solid material into the reduction zone, and reduction of the raw gas in the reduction zone by means of the pyrolyzed solid material into a fuel gas.

In addition, the method of gasification may be further refined either alternatively or in parallel to the above, such that the tar content in the raw gas that is generated can be measured, either directly or indirectly, with the help of the measurement unit, and/or the CO content in the product gas that is generated can be measured in a parallel operation with the help of a second measurement unit, and the supply of air provided via a second air supply device or, in the parallel use of both measurements, via a third air supply device can be adapted according to the associated measurement results, which are processed by means of signal technology.

The direct transfer of components of the pyrolysis gas that is generated without prior oxidation into the reduction zone can be prevented with the help of the supply of air, which is controlled as a function of the tar content. The determination of the indirect tar content can thereby be performed using a CH₄ sensor.

When supplying air as a function of the CO content, supplying air immediately before the transition from the gasification zone into the reduction zone is especially advantageous, since the pyrolyzed solid coke is once again heated immediately before entering the reduction zone, and the subsequent reduction of the raw gas with the help of the coke can progress in an especially effective manner in this case.

The method of gasification can be further refined alternatively or in parallel to the above, in that the method comprises the step of extracting the combustible gases using a gas extraction device, wherein the gas extraction device has a suction opening located to the side on the gasification apparatus, and configured such that the method is configured to have a uniform speed distribution across the cross-section of the gasifier for the gas being extracted, in that the gas extraction device has a ring, which provides the gas with a large outlet cross section on the side facing away from the outlet opening, and which tapers on the side facing the outlet opening.

The invention will be explained in greater detail below on the basis of non-limiting examples of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a longitudinally sectioned side view of a preferred embodiment of the gasification apparatus according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in FIG. 1. However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical charac-teristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

FIG. 1 shows a preferred embodiment of the present shaft gasifier 1. The solid material can be supplied to the gasification zone 2 by means of the solid material filler inlet 9, which gasification zone encloses the centrally located oxidation zone 3 on all sides in a horizontal cross section. In the case of a cylindrical embodiment as shown in FIG. 1, this results in an annular gasification zone, which takes shape about the oxidation zone, which is separated therefrom by the wall 14 of the oxidation zone, however, which is in thermal contact thereto in the case of a corresponding configuration of the wall 14. Air is supplied to the oxidation zone 3 via an air supply pipe 11, which is enclosed by a casing pipe 12, and which preferably extends centrally in longitudinal direction along the middle axis of the gasifier. However the air supply pipe may also be disposed outside of the longitudinal axis or laterally, in a radial direction, and may extend parallel to that longitudinal axis. The oxidation zone preferably has a bell-shaped configuration, wherein the upper part 13, which slopes downward tapered from the top to the bottom, facilitates the supply of the solid material into the gasification zone solely on the basis of gravity.

In the upper part of the oxidation zone 3, the wall 14 has openings 15 that face obliquely downward, by means of which openings the pyrolysis gas that arises in the gasification zone passes into the oxidation zone as a result of the pressure and flow conditions. The openings are formed in that the sloped wall ends at the height of the respective opening, and is continued just above said opening, being displaced radially inwardly. The thus slightly overlapping, obliquely descending walls 13 of the oxidation zone prevent the unwanted inflow of the solid material into the oxidation zone or a blockage of the opening by the carried solid material.

An individually adjustable quantity of air is supplied to the gasification zone 2 via air nozzles 4, 5, 6, which extend in a radial direction to the middle axis of the gasifier and which are distributed at regular or irregular intervals along the circumference of the shaft gasifier. Air for maintaining the temperature needed for the processes occurring in the upper part of the shaft gasifier is injected via the air supply device 4 in the first level. In so doing, a temperature measurement unit 7 measures the temperature in or in the immediate vicinity of the oxidation chamber and the supply of air via the air supply device 4 is adjusted accordingly on the basis of measurement results that are processed by means of signal technology so that preferably a temperature of approximately 1000° C. prevails in the oxidation zone.

While the majority of the pyrolysis gas that arises then passes through the oxidation zone along the provided path, it is unavoidable that a fraction of said gas penetrates into the reduction zone 8 directly from the gasification zone. In order to prevent a contamination of the oxidized pyrolysis gas from thus occurring, additional air is supplied to the gasification zone with the help of a second air supply device 5, which is positioned downstream from the first air supply device 4 when in the operational position, in order to oxidize the leaked gases directly in the gasification zone 2. The necessary quantity of air that must be supplied is determined with the aid of the measurement unit 10, which directly or indirectly measures the tar content of the product gas that is generated, and is adjusted via a control unit that is connected by means of signal technology as a function of measured values that are processed by means of signal technology.

Such oxidation of the leaked gases results in local temperature increases in the pyrolyzed solid material, the coke, which is to reduce the oxidized pyrolysis gas in the reduction zone by means of an endothermic reaction such that a preceding temperature increase has an entirely positive effect. In order to be able to adjust the temperature of the coke independently of the quantity of air injected in the second air supply level, either without preceding oxidation of leaked gases via a second air supply device or, as indicated in FIG. 1, in addition thereto, air is injected into the gasification zone via an additional air supply device 6 immediately before the coke is transferred from the gasification zone 2 into the reduction zone 8 so that the oxidized pyrolysis gas and the coke converge in the reduction zone at preferably 1000° C. A measurement of the CO content on the final product gas can provide information concerning the efficiency of the reduction process. The measurement unit 10 either directly or indirectly measures the CO content of the product gas so that, by processing the measured values by means of signal technology, the control unit can adjust the supply of air from the third air supply device 6 as a function of the measurement results obtained.

In the lower part of the gasifying apparatus depicted in FIG. 1, the gas that is generated is extracted via an outlet opening 16. In order to obtain a uniform speed of the gas that is generated across the cross section of the gasifier, a suction ring 17, which encloses the reduction zone, is configured in such a way the ring has the largest outlet cross section 18 on the side facing the outlet opening, which tapers as it approaches the outlet opening so that the side directly in front of the outlet opening provides the smallest outlet cross section.

It is to be understood that variations and modifications can be made on the aforementioned structure and method without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise. 

1-17. (canceled)
 18. A gasification apparatus for generating a combustible product gas from a solid material, comprising: a gasification zone, into which the solid material can be filled via a solid material filler inlet, and from which solid material a pyrolysis gas is generated; an oxidation zone for the oxidation of the generated pyrolysis gas, which is connected to the gasification zone in order to run the pyrolysis gas generated in the gasification zone into the oxidation zone; and wherein a first air supply device and a second air supply device supply air into the gasification zone, wherein the second air supply device follows the first air supply device in the processing direction of the solid material; a measurement unit for determining a qualitative or quantitative quantity of predetermined gas components of the flammable product gas, and from which generates test signals; and a control unit, which is coupled with the measurement unit by means of signal technology in order to transmit the test signals, and which is configured in such a way that the control unit controls the quantity of the air being supplied by the first and/or second air supply devices as a function of the test signals.
 19. The gasification apparatus according to claim 18, wherein the gasification zone and the oxidation zone are in thermal contact, wherein either the oxidation zone encloses the gasification zone in a cross section of the shaft gasifier in the direction of material flow of the solid material, or the gasification zone encloses the oxidation zone in a cross section of the shaft gasifier in the direction of material flow of the solid material, and wherein the gasification zone is preferably subdivided into a plurality of gasification sectors each having individually controllable air supply, which zones are regularly or irregularly distributed across the cross section.
 20. The gasification apparatus according to claim 18, wherein in an operating position in the direction of gravity, the gasification zone is disposed below a solid material filler inlet for the filling of solid material under the effect of gravity.
 21. The gasification apparatus according to claim 18, further comprising a reduction zone, which is connected to the oxidation zone in order that the raw gas formed in the oxidation zone be supplied to said reduction zone, and which is designed to chemically reduce the raw gas supplied thereto.
 22. The gasification apparatus according to claim 21, wherein the reduction zone is disposed below the gasification zone in the direction of gravity and is connected thereto for the direct transfer of solid material under the effect of gravity from the gasification zone into the reduction zone, and a section of the oxidation zone is disposed to separate the gasification zone from the reduction zone in the direction of flow of the gas that is generated.
 23. The gasification apparatus according to claim 18, wherein the measurement unit directly or indirectly measures the tar content of the raw gas or of the product gas that is generated, and wherein the control unit controls the quantity of air that is supplied via the second air supply device as a function of the tar content of the raw gas or of the product gas that is generated.
 24. The gasification apparatus according to claim 23, wherein the measurement unit is a CH₄ sensor, which is configured to convey indirect information concerning the tar component of the raw gas or the product gas via processing by means of signal technology.
 25. The gasification apparatus according to claim 21, wherein the measurement unit is designed in such a way that it directly or indirectly measures the CO content of the product gas that is generated, and in that the control unit controls the quantity of the air supplied by the second air supply device as a function of the CO content of the product gas that is generated in response to the measurement unit.
 26. The gasification apparatus according to claim 25, wherein the second air supply device is located directly above the transition from the gasification zone into the reduction zone.
 27. The gasification apparatus according to claim 18, further comprising a gas extraction device, which has a suction opening located to the side on the gasification apparatus, and wherein the gas extraction device comprises a suction ring, which is configured such that it generates a uniform speed distribution across the cross section of the gasification apparatus for the gas being extracted, in that the ring provides the gas with a large outlet cross section on the side facing away from the outlet opening, and which tapers on the side facing the outlet opening.
 28. A gasification method for generating a combustible product gas from a solid material, comprising the steps of: supplying a solid material into a gasification zone; gasification of the solid material in the gasification zone by means of pyrolysis or gasification to generate a pyrolysis gas; supplying the pyrolysis gas that is generated in the gasification zone to an oxidation zone; supplying air into a gasification zone through a first air supply device; and positioning a second air supply device downstream from the first air supply device in a processing direction of the solid material, wherein the supply of air via the second air supply device is controlled as a function of a measurement of the qualitative or quantitative quantity of a predetermined component of the gas in the raw gas that is generated in the oxidation zone or in a combustible product gas.
 29. The method of gasification according to claim 28, wherein the supply of air into the gasification zone is individually controlled within one or more gasification sectors that are either regularly or irregularly distributed across a cross section of the gasification zone.
 30. The method of gasification according to claim 28, further comprising the steps of: supplying air into the oxidation zone and conversion of the pyrolysis gas in a stoichiometric process by means of partial oxidation and cracking into a raw gas in the oxidation zone; supplying raw gas from the oxidation zone into a reduction zone; supplying partially or completely pyrolyzed solid material into the reduction zone; and chemically reducing the raw gas in the reduction zone by means of the pyrolyzed solid material into the combustible product gas.
 31. The method of gasification according to claim 28, wherein a tar content in the raw gas or product gas that is generated is measured directly or indirectly, and the quantity of air supplied via the second air supply device is supplied as a function of one or more test signals which are processed by means of signal technology.
 32. The method of gasification according to claim 31, wherein the CH₄ content of the product gas that is generated is measured to draw direct or indirect conclusions concerning the tar content of the raw gas or product gas via signal technology processing and controlling the supply of aid from the second air supply device as a function of this measurement.
 33. The method of gasification according to claim 30, wherein the CO content of the product gas that is generated in the reduction zone is measured, and the quantity of air that is supplied by the second air supply device is controlled as a function of the detected CO content.
 34. The method of gasification according to claim 28, further comprising: extraction of combustible gases using a gas extraction device, which has a suction opening located to the side on the gasification apparatus, and which is configured in such a way that it generates a uniform speed distribution across the cross section of a gasification apparatus for the gas being extracted, and wherein the gas extraction device has a suction ring, which provides the gas with a large outlet cross section on the side facing away from the outlet opening, and which tapers on the side facing the outlet opening. 